Process of making stencils.



No. 848,557. PATENTED MAR. 26, 1907.

A. D. KLABBR.

PROCESS OF MAKING STENOILS. APPLICATION FILED NOV. so. 1906.

WITNESSES:

W P MM 7 ATTORNEY member of the addressing-machine, sheets iinrrnn srATEs PATEN AUGUSTUS D. KLABER, OF LONDON, ENGLAND.

PROCESS oF'mAKINe STENCILS.

This invention relates to a process of male ing stencilgsheets for the duplication of typewritten or autographic matter.

The object of the invention is to provide a process of manufacturing stencil-sheets possessing great strength, such that they will be capable of use under conditions much more severe than these to which the stencil-sheets as now commonly made may be subjected.

The invention is directed particularly to the production of stencil-sheets which may.

be used in addressing-machines, though the sheets made in accordance with the process may be used as well in other ways. In such machines a movable member isemployed,

which is brought down upon a suitable stenoil toforce the duplicating-ink through the interstices therein and upon a letter, envelop, wrapper, or other article supported on a suitable platen. The stencil-sheets now in commen use consist of an open porous base having thereon a wax-like coating, such as paraffin. The base is usually a sheet of tissuepaper of open fibrous construction, such as that known as yo'shino paper, and the Wax-like coating of paraffin is applied to both sides thereof. On account of theblow upon the stencil-sheet struck by the movable constructed in this manner are not suited for such use.

My invention consists in applying to a suitable stencil-sheet-as,'for instance, one constructed in the manner above described'a 'strengtheningfilm which may consist of any suitable varnish. This strengthening-film is applied to the sheet after the stencil is cut and for that reason must be so applied as not to settle in the interstices cut in the sheet. The preferred manner of preventing such clogging of the interstices by the strengthening compound is by causing a flow of air through the interstices cut in the. stencil, either while applying the strengthening com pound thereto or immediately after such application and before the film has dried. In this way a sheet is obtained having the characters cut therein and strengthened sufii;

ciently to withstand the conditions of use in Specification of Letters Patent.

Application filed November 30, 1906, Serial No. 345.619.

- these strains.

Patented March 26, 1907.

an addressing-machine without even partially closing the interstices through which the duplicating-ink is to be forced to print the characters upon the envelop or other impression-sheet.

The invention is independent of the form of apparatus used in the manufacture of the sheet, and any suitable apparatus'may be employed for the purpose. The base of the sheet may consist of the open porous tissue,

as above described, or of a sheet of silk bolting-eloth, the latter being preferred in some cases because of its greater strength. To this sheet is applied the wax-like coating of parafiin in the manner now common in the manufacture of stencil-sheets for duplicating I upon such machines as the well-known mimeograph. With the sheet thus formed the operation of cutting the stencil is performed, this consisting in removing the Wax along the lines of the characters to be printed in any suitable manner. The cutting of the stencil is usually effected by placing the sheet in a type-writing machine and operating the type-writer in the usual manner, the blow of the type upon the shectserving to remove the Wax therefrom along the lines of the characters to'be printed. If desired, the operation of cutting the stencil may be performed by hand, using a pointed stylus with which to remove the wax-like coating. After the stencil has been cut the strengthening-film is applied. thereto. This may be done in any desired manner, as by drawing the sheet through a bath of a suitable varnish or by a plying the varnish to the sheet with a brush. Any suitable strengthening coin ound may be used, but preferably one which dries very quickly. I have used a shellac varnish with good results, and a volatile linseed-oil com pound may also be employed. While ap lymg the strengthening compound to the s eet or immediately thereafter and before the compound has dried currents of air are caused to flow through the interstices in the stencil-sheet alon the lines of the characters to be printed, such as will prevent any of the compound from settling and drying in these interstices, so as to partially or entirely clog them. During this operation the sheet should not be subjected to too great a strain, since otherwise it will be torn before the strengthening compound has hardened to such an extent as to assist in withstanding I have found it desirable'to support the sheet upon bristles while forcing the air through the interstices, so that the sheet will be supported at a multiplicity of distributed points, all of these oints being very small, so as not to impede t e flow of air through the interstices. This operation is continued while the strengthening compound is drying and hardening, little time being required for this purpose, since the strengthenin compound dries very quickly.

y this process a stencil-sheet is provided clear and Well defined as those obtained with a sheet not provided with the strengthening compound. The sheet thus made Is therefore well adapted for use upon an addressinge machine, with which the stencil is subjected to severe strains occasioned by the blow thereon necessary to force the duplicatingink through the interstices.

I have illustrated in the accompanying drawings a type of apparatus which may be employed in practicing the process, Figure 1 being a central-sectionof a coating-pan, and Fig. 2 a similar view of a drying device.

Referring first to Fig. 2, A indicates a pan having a plate B mounted therein a little above the bottom. Inthis plate are a plurality of distributed openings 6. Secured on and extending upwardly from plate B are bristles 0, all of the same length and cpvering practically the entire surfaceof the plate. A

' pipe a enters the bottom of pan A and has a cock 0/ the'rein. This pipe connects with a pump for drawing air from the pan.

If the stencil-sheet D is to be coated with the strengthening-film on one side only, it is laid The interupon the ends of the bristles Cand the film applied to its upper surface, as with a brush. The pump then draws air through the interstices in the stencil-sheet between the several bristles and through the openings 6 in plate B, pan A, and pipe (1 while the film is hardening, and thus prevents'the film from settling in and clogging the interstices in the sheet. When the film has dried, the cock a is turned ofi, the sheet renioved, and another one is similarly treated.

If it is desired to coat the sheet with the strengthening-film on both sides, a pan E for the strengthening-varnish e is arranged close to the pan A. The operator grasps a sheet at two of the corners and passes it through the bath of varnish e, so that all partszof the sheet become immersed and on taking it out carries it over to and lays it upon the bristles O. The operation of drying the film is then Having now described my invention, what I claim as new therein, and desireto secure by Letters Patent, is as follows:

1. The process of making stencils which consists in cutting the characters to be reproduced in a stencil-sheet, then applying a strengthening compound to the sheet, and causing a flow of air through the interstices formed in cutting the stencil to prevent the compound from clogging the interstices, substantially as set forth.

2. The process of making stencils consisting in cutting the characters to be reproduced in a stencil-sheet, then coating the sheet with a quick-drying varnish, and causing a flow of air through the interstices formed in cutting the stencil before the varnish has dried to prevent the varnish fromclogging the interstices, substantially as set forth.

This specification signed and witnessed this 21st day of November, 1906.

AUGUSTUS D. KLABER.

Witnesses:

I. MoINTosH,

D. S. EnMoNDs.

performed in the manner above described. 

